Australia is a constitutional democracy based on a federal division of powers. The constitutional basis of government consists of:

the Commonwealth Constitution, including amendments

state and territory constitutions, including amendments

legislation passed by the Commonwealth Parliament and the state and territory parliaments

High Court judgments

significant conventions of responsible government adopted from the British (Westminster) system of government that are in use at the Commonwealth, state and territory levels of government.

COMMONWEALTH CONSTITUTION

The national Constitution is found in the Commonwealth of Australia Constitution Act 1900, a British Act that became law in July 1900 and came into force on 1 January 1901.

Any proposed law for the alteration of the Commonwealth Constitution must be passed by an absolute majority of each House of Parliament (except in circumstances specified in section 128 of the Constitution which permits a referendum to proceed if passed by only one chamber). It must also be submitted to a referendum of the electors in each state and territory. An amendment must be approved by a majority of the voters in a majority of the states and by a majority of all voters.

Since 1901, 44 proposed amendments have been submitted to referenda. The consent of the electors has been given in regard to eight matters:

1906 - election of senators

1910 - state debts

1928 - state debts

1946 - social services

1967 - Aboriginal people

1977 - Senate casual vacancies

1977 - retirement age for federal judges

1977 - the right of territory electors to vote in constitutional referenda.

Each state and territory has its own constitution found in legislation. Where a law of a state is inconsistent with a law of the Commonwealth, the latter law prevails and the former law is, to the extent of the inconsistency, invalid.